US5024973A - Crystallized glass tooth crown material - Google Patents

Crystallized glass tooth crown material Download PDF

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Publication number
US5024973A
US5024973A US06/943,828 US94382886A US5024973A US 5024973 A US5024973 A US 5024973A US 94382886 A US94382886 A US 94382886A US 5024973 A US5024973 A US 5024973A
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component
mol
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tooth crown
crystallized glass
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US06/943,828
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Kazuo Kondo
Masahiko Okuyama
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Niterra Co Ltd
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NGK Spark Plug Co Ltd
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    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C4/00—Compositions for glass with special properties
    • C03C4/0007—Compositions for glass with special properties for biologically-compatible glass
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/15—Compositions characterised by their physical properties
    • A61K6/16—Refractive index
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/802—Preparations for artificial teeth, for filling teeth or for capping teeth comprising ceramics
    • A61K6/822—Preparations for artificial teeth, for filling teeth or for capping teeth comprising ceramics comprising rare earth metal oxides
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/802—Preparations for artificial teeth, for filling teeth or for capping teeth comprising ceramics
    • A61K6/824—Preparations for artificial teeth, for filling teeth or for capping teeth comprising ceramics comprising transition metal oxides
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
    • A61K6/00—Preparations for dentistry
    • A61K6/80—Preparations for artificial teeth, for filling teeth or for capping teeth
    • A61K6/831—Preparations for artificial teeth, for filling teeth or for capping teeth comprising non-metallic elements or compounds thereof, e.g. carbon
    • A61K6/836—Glass
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C—CHEMISTRY; METALLURGY
    • C03—GLASS; MINERAL OR SLAG WOOL
    • C03C—CHEMICAL COMPOSITION OF GLASSES, GLAZES OR VITREOUS ENAMELS; SURFACE TREATMENT OF GLASS; SURFACE TREATMENT OF FIBRES OR FILAMENTS MADE FROM GLASS, MINERALS OR SLAGS; JOINING GLASS TO GLASS OR OTHER MATERIALS
    • C03C10/00—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition
    • C03C10/0054—Devitrified glass ceramics, i.e. glass ceramics having a crystalline phase dispersed in a glassy phase and constituting at least 50% by weight of the total composition containing PbO, SnO2, B2O3

Definitions

  • the present invention relates to a crystallized glass tooth crown material.
  • Materials for use in living bodies e.g., in prosthesis, redintegration, correction, etc., in the field of dentistry have conventionally been made of metals, such as alloys of one or more of Cr, Fe, Co, Ni, Cu, Zn, Be, Cd, and Au. These metals excusive of Au are also typically somewhat deficient in chemical resistance. Thus there is some tendency for oxidation and discoloration to occur during the storage or use, and, furthermore, there is a possibility of the metals exerting adverse influences on the living body. Au is very expensive. Further, the materials for use in living bodies have been made of plastics, composites containing resin and inorganic filler, or inorganic ceramics. However, the plastics lack in an affinity for living body, the composites are easy to discolor and exert adverse influences on the living body, and the ceramics are difficult to be applied to tooth crown materials due to their shrinking during sintering.
  • An object of the present invention is to provide a crystallized glass tooth crown material which is superior in chemical resistance, particularly water resistance, has a good appearance and has almost the same mechanical strength and hardness as those of the enamel of the human teeth.
  • a material satisfying the object of the present invention has now been found, viz., a crystallized glass tooth crown material consisting essentially of from 40 to 75 mol % component X, from 20 to 55 mol% component Y and from 0.1 to 10 mol% component Z, wherein
  • component X is P 2 O 5 ,
  • component Y is selected from ZnO, K 2 O, B 2 O 3 and Al 2 O 3 in an amount of up to 20 mol% and CaO and BaO in an amount of up to 55 mol%, and
  • component Z is selected from SrO, Ta 2 O 5 , La 2 O 3 , CeO 2 and Nb 2 O 5 .
  • the chemical resistance as described above generally means durability against water or various chemical agents such as HCl, H 2 SO 4 , HNO 3 or etc.
  • the materials which are superior in water resistance are in general superior in chemical resistance.
  • P 2 O 5 is a main component of phosphate glass. If the P 2 O 5 content is less than 40 mol%, the frit is difficult to melt. On the other hand, if it is in excess of 75 mol%, the frit is unstable and lacks water resistance, and a frit quenched in water hydrates quickly.
  • Component Y is added to the P 2 O 5 , which is an acid component, thereby changing it from acidic to neutral, and chemically stabilizing it. If the proportion of Component Y is less than 20 mol%, the frit is unstable and poor in water resistance, and a frit quenched in water hydrates quickly. On the other hand, if it is in excess of 55 mol%, the frit is difficult to melt and cannot exhibit the desired effects.
  • component Z bonds to sites of the P 2 O 5 -base glass which readily adsorb a hydroxyl group(--OH), and serve to stabilize the glass by which not only water resistance but also chemical resistance are increased. If the proportion of component Z is less than 0.1 mol%, the desired effect cannot be obtained. On the other hand, if it is in excess of 10 mol%, the water resistance tends to be reduced.
  • the preferred embodiment of the present invention is a crystallized glass tooth crown material consisting essentially of from 40 to 60 mol% component X, from 40 to 55 mol% component Y and from 1 to 8 mol% component Z, wherein
  • component X is P 2 O 5 ,
  • component Y is selected from ZnO, K 2 O, B 2 O 3 and Al 2 O 3 in an amount of up to 20 mol% and CaO and BaO in an amount of up to 50 mol%, and
  • component Z is selected from SrO, Ta 2 O 5 , La 2 O 3 , CeO 2 and Nb 2 O 5 .
  • the more preferred embodiment of the present invention is a crystallized glass tooth crown material consisting essentially of from 40 to 60 mol% component X, from 40 to 55 mol% component Y and from 1 to 8 mol% component Z, wherein
  • component X is P 2 O 5 ,
  • component Y is selected from K 2 O and B 2 O 3 in amount of up to 20 mol% and CaO and BaO in an amount of up to 50 mol%, and
  • component Z is selected from SrO, La 2 O 3 and CeO 2 .
  • K 2 O, B 2 O 3 , CaO and/or BaO are preferred because of providing good affinity for living body.
  • SrO, La 2 O 3 and/or CeO 2 are also preferred because of providing good affinity for living body.
  • ammonium secondary phosphate (NH 4 ) 2 HPO 4 ) and ammonium tertiary phosphate ((NH 4 ) 3 PO 4 ) can be used.
  • the carbonates and hydroxides of the respective metals which are converted into the above oxides upon heating, can be used.
  • the metals may be used in the form of compounds in combination with phosphoric acid, the examples of which compounds include Ca 3 (PO 4 ) 2 , Zn 3 (PO 4 ) 2 , AlPO 4 , K 3 PO 4 and Ba 3 (PO 4 ) 2 .
  • the oxides SrO, Ta 2 O 5 , La 2 O 3 , CeO 2 , and Nb 2 O 5 may be used directly in the oxide form, or as the carbonates and hydroxides of the respective metals can be used, or use can be in the form of compounds of the metals in combination with phosphoric acid.
  • the above starting materials are pulverized and mixed in a mixer such as a trommel, mixer-blender, etc., melted at 1,000° C. to 1,200° C in a crucible made of a refractory substance, such as alumina, mullite, or platinum, poured into a metallic mold maintained at 600° C. to 700° C., molded into a form of tooth crown while at the same time cooling quicly and glassifying, raised in temperature to a temperature 50° C. higher than the crystallization temperature at a temperature-raising rate of from 50° C. to 200° C./hr, maintaining the material at that temperature for from 1 to 3 hours, and then cooling at a cooling rate of from 50° C. to 300° C./hr.
  • a crystallized glass tooth crown material which has a milk white color closely approximating that of human teeth.
  • H 3 PO 4 , BaCO 3 , CaCO 3 , MgCO 3 , ZnO, H 3 BO 3 , Al 2 O 3 , SrO, Ta 2 O 5 , La 2 O 3 , CeO 2 and Nb 2 O 5 were weighed out to form compositions as shown in Table 1 at the time of formation of the frit, and mixed, melted at 1,000° C. to 1,200° C. in a platinum crucible, poured into a metallic mold, and molded into the form of a tooth crown while at the same time quickly cooling with water and glassifying. Then the tooth crown materials were raised in temperature to a temperature 50° C.
  • Crystallized glass materials AR and IR are comparative products, and the others are the products of the present invention.
  • the coefficient of linear thermal expansion of the crystallized glass tooth crown material of the present invention is near that of the enamel of the human teeth (i.e., 11.4 ⁇ 10 -6 /° C. (30-400° C.)). For this reason, the difference in expansion between the crystallized glass tooth crown material and human teeth is small.
  • the crystallized glass tooth crown material of the present invention is excellent in matching the expansions and contractions of tooth enamel which it may contact.

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  • Health & Medical Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Oral & Maxillofacial Surgery (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Epidemiology (AREA)
  • Veterinary Medicine (AREA)
  • Public Health (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Plastic & Reconstructive Surgery (AREA)
  • General Chemical & Material Sciences (AREA)
  • Geochemistry & Mineralogy (AREA)
  • Materials Engineering (AREA)
  • Organic Chemistry (AREA)
  • Dispersion Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Molecular Biology (AREA)
  • Glass Compositions (AREA)
  • Dental Preparations (AREA)

Abstract

A crystallized glass tooth crown is described, consisting essentially of from 40 to 75 mol % component X, from 20 to 55 mol % component Y and from 0.1 to 10 mol % component Z, wherein
component X is P2 O5,
component Y is selected from ZnO, K2 O, B2 O3 and Al2 O3 in an amount of up to 20 mol % and additionally CaO and BaO in an amount to bring the total mol % of component y to up to 55 mol %, and
component Z is selected from SrO, Ta2 O5, La2 O3, CeO2 and Nb2 O5.
This tooth crown and is superior in chemical resistance, has a good appearance, and has almost the same mechanical strength and hardness as those of the enamel of the human teeth.
A process for producing crystallized glass tooth crown is also described.

Description

This is a continuation of application Ser. No. 719,103, filed Apr. 2, 1985, and now abandoned.
FIELD OF THE INVENTION
The present invention relates to a crystallized glass tooth crown material.
BACKGROUND OF THE INVENTION
Materials for use in living bodies, e.g., in prosthesis, redintegration, correction, etc., in the field of dentistry have conventionally been made of metals, such as alloys of one or more of Cr, Fe, Co, Ni, Cu, Zn, Be, Cd, and Au. These metals excusive of Au are also typically somewhat deficient in chemical resistance. Thus there is some tendency for oxidation and discoloration to occur during the storage or use, and, furthermore, there is a possibility of the metals exerting adverse influences on the living body. Au is very expensive. Further, the materials for use in living bodies have been made of plastics, composites containing resin and inorganic filler, or inorganic ceramics. However, the plastics lack in an affinity for living body, the composites are easy to discolor and exert adverse influences on the living body, and the ceramics are difficult to be applied to tooth crown materials due to their shrinking during sintering.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a crystallized glass tooth crown material which is superior in chemical resistance, particularly water resistance, has a good appearance and has almost the same mechanical strength and hardness as those of the enamel of the human teeth.
Based on extensive investigations, a material satisfying the object of the present invention has now been found, viz., a crystallized glass tooth crown material consisting essentially of from 40 to 75 mol % component X, from 20 to 55 mol% component Y and from 0.1 to 10 mol% component Z, wherein
component X is P2 O5,
component Y is selected from ZnO, K2 O, B2 O3 and Al2 O3 in an amount of up to 20 mol% and CaO and BaO in an amount of up to 55 mol%, and
component Z is selected from SrO, Ta2 O5, La2 O3, CeO2 and Nb2 O5 .
DETAILED DESCRIPTION OF THE INVENTION
The chemical resistance as described above generally means durability against water or various chemical agents such as HCl, H2 SO4, HNO3 or etc. The materials which are superior in water resistance are in general superior in chemical resistance.
The reasons why the proportions of components X, Y and Z in the crystallized glass tooth crown material of the present invention are limited to the above-specified ranges are hereinafter described in detail.
P2 O5 is a main component of phosphate glass. If the P2 O5 content is less than 40 mol%, the frit is difficult to melt. On the other hand, if it is in excess of 75 mol%, the frit is unstable and lacks water resistance, and a frit quenched in water hydrates quickly.
Component Y is added to the P2 O5, which is an acid component, thereby changing it from acidic to neutral, and chemically stabilizing it. If the proportion of Component Y is less than 20 mol%, the frit is unstable and poor in water resistance, and a frit quenched in water hydrates quickly. On the other hand, if it is in excess of 55 mol%, the frit is difficult to melt and cannot exhibit the desired effects.
It has also been found according to the present invention that component Z bonds to sites of the P2 O5 -base glass which readily adsorb a hydroxyl group(--OH), and serve to stabilize the glass by which not only water resistance but also chemical resistance are increased. If the proportion of component Z is less than 0.1 mol%, the desired effect cannot be obtained. On the other hand, if it is in excess of 10 mol%, the water resistance tends to be reduced.
The preferred embodiment of the present invention is a crystallized glass tooth crown material consisting essentially of from 40 to 60 mol% component X, from 40 to 55 mol% component Y and from 1 to 8 mol% component Z, wherein
component X is P2 O5,
component Y is selected from ZnO, K2 O, B2 O3 and Al2 O3 in an amount of up to 20 mol% and CaO and BaO in an amount of up to 50 mol%, and
component Z is selected from SrO, Ta2 O5, La2 O3, CeO2 and Nb2 O5.
The more preferred embodiment of the present invention is a crystallized glass tooth crown material consisting essentially of from 40 to 60 mol% component X, from 40 to 55 mol% component Y and from 1 to 8 mol% component Z, wherein
component X is P2 O5,
component Y is selected from K2 O and B2 O3 in amount of up to 20 mol% and CaO and BaO in an amount of up to 50 mol%, and
component Z is selected from SrO, La2 O3 and CeO2.
For component Y, K2 O, B2 O3, CaO and/or BaO are preferred because of providing good affinity for living body.
For component Z, SrO, La2 O3 and/or CeO2 are also preferred because of providing good affinity for living body.
Lost wax process as well known in the field of dentistry can be applied to the production of the crystallized glass tooth crown material of the present invention.
A process for the production of the crystallized glass tooth crown material of the present invention is described below.
For component X, in addition to orthophosphoric acid (H3 PO4), ammonium secondary phosphate ((NH4)2 HPO4) and ammonium tertiary phosphate ((NH4)3 PO4) can be used.
For component Y, in addition to directly using the oxides ZnO, K2 O, B2 O3, Al2 O3, CaO, and BaO, the carbonates and hydroxides of the respective metals, which are converted into the above oxides upon heating, can be used. In addition, the metals may be used in the form of compounds in combination with phosphoric acid, the examples of which compounds include Ca3 (PO4)2, Zn3 (PO4)2, AlPO4, K3 PO4 and Ba3 (PO4)2 .
For component Z, analogously to component Y, the oxides SrO, Ta2 O5, La2 O3, CeO2, and Nb2 O5 may be used directly in the oxide form, or as the carbonates and hydroxides of the respective metals can be used, or use can be in the form of compounds of the metals in combination with phosphoric acid.
The above starting materials are pulverized and mixed in a mixer such as a trommel, mixer-blender, etc., melted at 1,000° C. to 1,200° C in a crucible made of a refractory substance, such as alumina, mullite, or platinum, poured into a metallic mold maintained at 600° C. to 700° C., molded into a form of tooth crown while at the same time cooling quicly and glassifying, raised in temperature to a temperature 50° C. higher than the crystallization temperature at a temperature-raising rate of from 50° C. to 200° C./hr, maintaining the material at that temperature for from 1 to 3 hours, and then cooling at a cooling rate of from 50° C. to 300° C./hr. Thus there is produced a crystallized glass tooth crown material, which has a milk white color closely approximating that of human teeth.
The present invention is described in greater detail with reference to the following example.
EXAMPLE
H3 PO4, BaCO3, CaCO3, MgCO3, ZnO, H3 BO3, Al2 O3, SrO, Ta2 O5, La2 O3, CeO2 and Nb2 O5 were weighed out to form compositions as shown in Table 1 at the time of formation of the frit, and mixed, melted at 1,000° C. to 1,200° C. in a platinum crucible, poured into a metallic mold, and molded into the form of a tooth crown while at the same time quickly cooling with water and glassifying. Then the tooth crown materials were raised in temperature to a temperature 50° C. higher than their crystallization temperatures as indicated in Table 1 at a rate of 100° C./hr, maintained at that temperature for 2 hours, and then cooled to room temperature at a rate of 100° C./hr, whereupon crystallized glassed AR to M were produced. Crystallized glass materials AR and IR are comparative products, and the others are the products of the present invention.
The characteristics of the above crystallized glass tooth crown materials are shown in Table 1.
                                  TABLE 1                                 
__________________________________________________________________________
                                 Coefficient                              
Crystallized                     of Linear                                
Glass                            Thermal Ex-                              
                                        Crystalli-                        
Tooth  Composition (mol %)       pansion                                  
                                        zation                            
Crown  Component                                                          
             Component                                                    
                    Component                                             
                           Transition                                     
                                 (30-400° C.)                      
                                        Temperature                       
Material                                                                  
       X mol %                                                            
             Y mol %                                                      
                    Z mol %                                               
                           Point (°C.)                             
                                 (/°C.)                            
                                        (°C.)                      
                                               Remarks                    
__________________________________________________________________________
AR     P.sub.2 O.sub.5                                                    
           47                                                             
             CaO 44     0  506   108 × 10.sup.-7                    
                                        666    Comparative                
             Al.sub.2 O.sub.3                                             
                 1                             example                    
             BaO 8                                                        
B      P.sub.2 O.sub.5                                                    
           47                                                             
             CaO 44 SrO 3  520   118 × 10.sup.-7                    
                                        690    Example of                 
             Al.sub.2 O.sub.3                                             
                 1                             this invention             
             BaO 5                                                        
C      P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  Ta.sub.2 O.sub.5                                      
                        3  532   104 × 10.sup.-7                    
                                        700    Example of                 
                                               this invention             
D      P.sub. 2 O.sub.5                                                   
           47                                                             
             BaO 5  La.sub.2 O.sub.3                                      
                        3  530   116 × 10.sup.-7                    
                                        678    Example of                 
                                               this invention             
E      P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  CeO.sub.2                                             
                        3  524   110 × 10.sup.-7                    
                                        690    Example of                 
                                               this invention             
F      P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  Nb.sub.2 O.sub.5                                      
                        3  532    94 × 10.sup.-7                    
                                        --     Example of                 
                                               this invention             
G      P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  SrO 6  500   125 × 10.sup.-7                    
                                        650    Example of                 
                                               this invention             
H      P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  SrO 8  470   140 × 10.sup.-7                    
                                        620    Example of                 
                                               this invention             
IR     P.sub.2 O.sub.5                                                    
           47                                                             
             BaO 5  SrO 15 450   160 × 10.sup.-7                    
                                        600    Comparative                
                                               example                    
J      P.sub. 2 O.sub.5                                                   
           46                                                             
             BaO 44 SrO 3  500   150 × 10.sup.-7                    
                                        710    Example of                 
             Al.sub.2 O.sub.3                                             
                 2                             this invention             
             MgO 5                                                        
K      P.sub.2 O.sub.5                                                    
           60                                                             
             CaO 5  SrO 3  498   110 × 10.sup.-7                    
                                        715    Example of                 
             BaO 10                            this invention             
             Al.sub.2 O.sub.3                                             
                 7                                                        
             ZnO 5                                                        
             MgO 5                                                        
             K.sub.2 O                                                    
                 5                                                        
L      P.sub.2 O.sub.5                                                    
           70                                                             
             CaO 5  SrO 3  560    93 × 10.sup.-7                    
                                        760    Example of                 
             Al.sub.2 O.sub.3                                             
                 7                             this invention             
             MgO 5                                                        
             B.sub.2 O.sub.3                                              
                 10                                                       
M      P.sub.2 O.sub.5                                                    
           60                                                             
             BaO 20 SrO 3  543   105 × 10.sup.-7                    
                                        720    Example of                 
             ZnO 17                            this invention             
__________________________________________________________________________
The above-produced crystallized glass tooth crown materials were allowed to stand in an atmosphere at 60° C. and 95% RH (relative humility), and the time until discoloration occurred was measured. The results are shown in Table 2.
              TABLE 2                                                     
______________________________________                                    
Crystallized                                                              
           Time taken                                                     
Glass Tooth                                                               
           for Discoloration                                              
Crown Material                                                            
           to occur (hours)                                               
                         Remarks                                          
______________________________________                                    
AR         300           Comparative example                              
B          more than 1,000                                                
                         Example of this                                  
                         invention                                        
C          more than 1,000                                                
                         Example of this                                  
                         invention                                        
D          900           Example of this                                  
                         invention                                        
E          800           Example of this                                  
                         invention                                        
F          600           Example of this                                  
                         invention                                        
G          more than 1,000                                                
                         Example of this                                  
                         invention                                        
H          more than 1,000                                                
                         Example of this                                  
                         invention                                        
IR         500           Comparative example                              
J          900           Example of this                                  
                         invention                                        
K          800           Example of this                                  
                         invention                                        
L          650           Example of this                                  
                         invention                                        
M          700           Example of this                                  
                         invention                                        
______________________________________
The coefficient of linear thermal expansion of the crystallized glass tooth crown material of the present invention is near that of the enamel of the human teeth (i.e., 11.4×10-6 /° C. (30-400° C.)). For this reason, the difference in expansion between the crystallized glass tooth crown material and human teeth is small. Thus the crystallized glass tooth crown material of the present invention is excellent in matching the expansions and contractions of tooth enamel which it may contact.
It can be seen from Table 2 that the crystallized glass tooth crown material of the present invention is superior in moisture resistance to the comparative glasses.
While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof.

Claims (7)

What is claimed is:
1. A crystallized glass tooth crown consisting essentially of from 40 to 75 mol% component X, from 20 to 55 mol% component Y and from 0.1 to 10 mol% component Z, wherein
component X is P2 O5,
component Y is selected from ZnO, K2 O, B2 O3, and Al2 O3 in an amount of up to 20 mol% and additionally CaO and BaO in an amount to bring the total mol% of component Y to up to 55 mol%, and
component Z is selected from SrO, Ta2 O5, La2 O3, CeO2 and Nb2 O5.
2. A crystallized glass tooth crown as claimed in claim 1, wherein said component X is in an amount of 40 to 60 mol%.
3. A crystallized glass tooth crown as claimed in claim 1, wherein said component Y is in an amount of 44 to 55 mol%.
4. A crystallized glass tooth crown as claimed in claim 1, wherein said component Z is in an amount of 1 to 8 mol%.
5. A crystallized glass tooth crown as claimed in claim 1, wherein said component Y is selected from ZnO, K2 O, B2 O3 and Al2 O3 in an amount of up to 20 mol% and additionally CaO and BaO in an amount to bring the total mol% of component Y to up to 50 mol%.
6. A crystallized glass tooth crown as claimed in claim 1, wherein said component Y is selected from K2 O and B2 O3 in an amount of up to 20 mol% and additionally CaO and BaO in an amount to bring the total mol% of component Y to up to 55 mol%.
7. A crystallized glass tooth crown as claimed in claim 1, wherein said component Z is selected from SrO, La2 O3 and CeO2.
US06/943,828 1984-04-02 1986-12-17 Crystallized glass tooth crown material Expired - Fee Related US5024973A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP59-65531 1984-04-02
JP59065531A JPS60210546A (en) 1984-04-02 1984-04-02 Crystallized glass for crown

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US06719103 Continuation 1985-04-02

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Cited By (7)

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US5236495A (en) * 1990-08-21 1993-08-17 Asahi Glass Company Ltd. Calcium phosphate type glass-ceramic
CN109195927A (en) * 2016-05-27 2019-01-11 康宁股份有限公司 Bioactivity boron phosphate glass
US20210070651A1 (en) * 2016-07-15 2021-03-11 Gc Corporation Dental glass and dental composition
US11274059B2 (en) 2017-11-28 2022-03-15 Corning Incorporated Bioactive glass compositions and dentin hypersensitivity remediation
US11384009B2 (en) 2017-11-28 2022-07-12 Corning Incorporated High liquidus viscosity bioactive glass
US11446410B2 (en) 2017-11-28 2022-09-20 Corning Incorporated Chemically strengthened bioactive glass-ceramics
US11814649B2 (en) 2016-05-27 2023-11-14 Corning Incorporated Lithium disilicate glass-ceramic compositions and methods thereof

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US3519445A (en) * 1967-11-06 1970-07-07 Corning Glass Works Al2o3-p2o5-b2o3 glass-ceramic articles and methods
US3751272A (en) * 1970-03-02 1973-08-07 Hoya Glass Works Ltd Colorless p{11 o{11 {11 glass with anomalous dispersion in short wavelength region
US3785835A (en) * 1971-05-21 1974-01-15 Hoya Glass Works Ltd Anomalous dispersion glass
US3940255A (en) * 1974-08-05 1976-02-24 Ferro Corporation Process for making cordierite glass-ceramic having nucleating agent and increased percent cordierite crystallinity
US4141738A (en) * 1978-03-16 1979-02-27 Owens-Illinois, Inc. Melt-formed polycrystalline ceramics and dopant hosts containing phosphorus
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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5236495A (en) * 1990-08-21 1993-08-17 Asahi Glass Company Ltd. Calcium phosphate type glass-ceramic
CN109195927A (en) * 2016-05-27 2019-01-11 康宁股份有限公司 Bioactivity boron phosphate glass
US11814649B2 (en) 2016-05-27 2023-11-14 Corning Incorporated Lithium disilicate glass-ceramic compositions and methods thereof
US20210070651A1 (en) * 2016-07-15 2021-03-11 Gc Corporation Dental glass and dental composition
US11274059B2 (en) 2017-11-28 2022-03-15 Corning Incorporated Bioactive glass compositions and dentin hypersensitivity remediation
US11384009B2 (en) 2017-11-28 2022-07-12 Corning Incorporated High liquidus viscosity bioactive glass
US11446410B2 (en) 2017-11-28 2022-09-20 Corning Incorporated Chemically strengthened bioactive glass-ceramics
US11999653B2 (en) 2017-11-28 2024-06-04 Corning Incorporated High liquidus viscosity bioactive glass

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JPS60210546A (en) 1985-10-23

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